Re: Random passwords and E-mail regex

[Roger Dingledine <arma@mit.edu>]

> Regular expression for E-mail address checking - here's what I came up
> with.  I have not tested it yet, and am not extremely familiar with
> regexes.  Anyone want to take a look and see if it can be improved upon?
> 
> if (!ereg("^\w+@\w+\.\w+$", $email))
> 
> (this is PHP remember, not Perl.  Hopefully the regex syntax is the
> same)
 
I can have a . or - in my username. Similarly, I can have more than two
words
in my domain -- the above limits you to foo@bar.baz.

Try \w[-.\w]* for the things on each side of the @, as a start. Probably
you'll want to consider adding + and similar, for people who sort their
mail like that. (\w == alphanumeric plus underscore, in my perl world.)

Domains can be checked more thoroughly, by checking if it's either 2 or 3
letters, and if 3 if it's a standard one. And beyond that, you can actually
verify the existence of the domain if you like. But that gets trickier to
keep robust.

--Roger